Shopping bag having reinforced walls

BACKGROUND OF THE INVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In producing the bag shown in FIGS. 1 and 2, two plastic 5 foils (3 and 4 in FIG. 2) are placed on either side of an intermediate Kraft paper sheet 5, the width of which corresponds to the length of the square bottom to be produced. The plastic foils which are wider than the paper sheet, have edge portions 6 and 7 projecting outside the longitudinal edges 8 and 9 (FIG. IQ 1) of the paper to form the end walls of the bag. The laminate thus obtained is folded double in forming transverse bellows fold 10 adapted to serve as bottom. The depth of said bellows fold 10 is equal to the width of each edge portion 6 and 7, respectively.

., The mating edges 11,12 of the foils brought together by the ³ following operation are heat sealed throughout their length so that the bellows fold is transformed into a pocket closed at both ends. Preferably the outer foil 3 is dimensioned to project slightly outside the transverse edges of the paper sheet 5 and -0 of the inner foil 4 at the open end of the bag, and these pro^υ jecting portions are folded back and cemented to the inside of the inner foil 4, as shown at 13 in FIG. 2.

In the known way, handles may be made integral with the bag-forming foils if the latter have sufficient strength, but if 25 the foils are made thin it may be more convenient to make ³ handle members of a stronger plastic material and attach them to the bag by heat sealing. In FIGS. 1 and 2, two rectangular pieces 14 of plastic foil have been folded double and applied such that their legs straddle the edge portions of the bag walls 3Q at the open end of the bag. One of the handle legs has been heat sealed to the outside of the outer foil 3 (at 15) and the other leg has been heat sealed to the inside of the inner foil 4. Each handle member 14 has a grip opening 16 formed therein. If the paper sheet 5 does not extend up to the handle members 35 14 the welds 15 can be through-going.

When the flattened bag shown in FIG. 1 is opened and the bottom is unfolded, the stiffening paper sheet contributes to giving the bag the square shape shown in FIG. 1, in that the edge portions 6,7 of file soft foils 3,4 located outside the paper ₄Q sheet are easily folded around the longitudinal edges 8,9 of the paper sheet while forming two end walls 17 which thus connect the two opposite stiffened sidewalls 18. At the formation of the stiffened square bottom 19 two triangular foil portions 20,21 indicated in FIG. 1 are formed between the bottom area 45 and each of the end walls 17. These triangular portions 20,21 are automatically folded inwards towards each other to form a triangular pocket 22 (FIG. 2) which contributes to an increased rigidity of adjacent end wall. The bag thus opened has a sufficient rigidity to stand by itself in the same way as an 50 empty paper bag.